1. Field of the Invention
The present invention relates to an apparatus and method for managing power, and more particularly, to an apparatus and method for stably managing power by comparing a predetermined reference voltage level with a battery voltage level. The present application is based on Korean Patent Application No. 2001-88232, which is incorporated herein by reference.
2. Description of the Related Art
A conventional system using a battery manages power by turning off the system when the voltage level of the battery drops below a predetermined voltage level. In the case where a system driven by the battery, e.g., a mobile telephone, is used continuously, when the battery voltage level drops below the predetermined voltage level, the system turns off. However, when detecting the battery voltage level after a specific period, the battery voltage level often returns to a level higher than the power off level.
Therefore, the conventional method for managing power repeatedly turns the power on and off because, after power-off the voltage level reaches a level higher than the power off level and power is turned on, but after a short period the voltage drops below the power off level and power is turned off. The power-on and power-off operations are repeated until the battery power is completely drained. This phenomenon may cause system failure or a fatal system defect.
To solve the above-described problems, it is an objective of the present invention to provide an apparatus for managing power, where a reference voltage level for managing battery power is established and the established reference voltage level is compared to the battery power, thereby stably managing the battery power by using the result of comparison.
It is another objective of the present invention to provide a method for managing power, where a reference voltage level for managing battery power is established and the established reference voltage level is compared to the battery voltage level to stably manage the battery power by using the result of the comparison.
To accomplish the above objective of the present invention, an apparatus for managing power includes a power control unit for detecting a battery voltage level of a battery, which supplies power to a system, after a predetermined period from powering off the system and for comparing the detected result with a reference voltage level so as to determine the supply of power to the system, and a power switching unit for operating the system in a normal mode when the battery voltage level is above the reference voltage level.
It is preferable that the power control unit outputs a signal for operating the system in a sleep mode in a case where the detected battery voltage level is between a power off voltage level and the reference voltage level.
To accomplish another objective of the present invention, a method for managing power includes (a) detecting a battery voltage level of a battery, which supplies power to a system after a predetermined period from powering off the system, and comparing the battery voltage level with a reference voltage level, and (b) deciding the operation of the system in correspondence to the result of the comparison.
It is preferable that if the detected battery voltage level is between a power off voltage level and the reference voltage level, the system is operated in a sleep mode. It is preferable that if the detected battery voltage level is above the reference voltage level, a switch for operating the system is turned on, thereby normally operating the system.